In the pedicure spa industry, hygiene is an important matter as it is easy to transfer infection and disease from one patient to another if those surfaces which make contact with a soaking solution receiving the patient's feet are not properly sanitized after each treatment.
For this reason, disposable liners were introduced to the industry which removed altogether the step of sanitization between treatments of different patients performed in a common basin. That is, an imperforate flexible disposable liner is placed to cover or line interior surfaces of the soaking basin of a foot spa apparatus, which otherwise would be in contact with the soaking solution. Thus, at the end of the treatment for a patient, the soaking solution can be drained and the used liner which may carry any skin cells, chemicals, and other potential contaminants is simply disposed of so that a new liner free of any potential contaminants can be installed in the same soaking basin for the following patient's treatment.
Typically, disposable liners of the type used in the pedicure spa industry are draped over a top rim of the soaking basin and depend downwardly therefrom to a bottom floor of the basin so that the floor and upstanding peripheral wall are fully covered by the liner. A surface of the soaking basin of the type receiving the liner is smooth and is uninterrupted other than by a drainage hole in the floor of the basin through which the soaking solution is discharged by gravity at the end of the treatment to empty the receptacle formed by the liner laid in the soaking basin, so that the used liner subsequently can be discarded. Drainage at the end of a treatment acts to puncture the initially imperforate liner at a location over the drainage hole so that the used soaking solution flows out by gravity. As the liner is now irreversibly perforated, particularly at a location registrable with the drainage hole, it is no longer suited for use to contain soaking solution, which is acceptable given that the used liner is to be discarded as waste.
Furthermore, in the pedicure spa industry it is desirable to purposefully cause the soaking solution to overflow for example when the soaking solution is not at a suitable temperature in which case water of the desired temperature is added while the soaking solution already contained within the basin of the less desirable temperature is displaced by overflowing out of the basin. One way in which overflow can be performed in a controlled manner is described in U.S. Pat. No. 9,289,353 to Ta where a portion of the top rim is lowered as if to form a spout across which the overflowing solution can escape from the basin. This arrangement is still suited for use with the imperforate flexible disposable liner, which, as in the conventional sense, drapes over the top rim including where it is lowered to form the spout for guiding the overflow, in order to properly cover the soaking basin to protect it from any potential contaminants.